A 350ft crop circle of an ancient Mayan symbol, said to be a sign of an impending apocalypse, has appeared next to Silbury Hill in Wiltshire. The giant pattern - thought to represent a traditional Mayan head-dress - appeared next to the tallest prehistoric man-made mound in Europe last week. Members of the crop circle community believe the mystic symbol is a signal of the end of the 5,126-year Mayan 'Long Count' calendar on December 21, 2012. Karen Alexander, a crop circle enthusiast, said: "This is one of the most interesting crop circles I have ever seen. It is definitely...